Centre Of Gravity Position
Calculator
Results
- Centre of gravity (in from datum)
- 89.760869
- Total weight (lb)
- 1,840
- Total moment (lb·in)
- 165,160
Aviation and marine results
| Centre of gravity (in from datum) | 89.760869 |
| Total weight (lb) | 1,840 |
| Total moment (lb·in) | 165,160 |
formula-map diagram
- Centre of gravity (in from datum)
- 89.760869
- Total weight (lb)
- 1,840
- Total moment (lb·in)
- 165,160
Aviation and marine relationship
Formula
CG = Σ(weight × arm) ÷ Σ weight= 89.760869565217
Note
This is a simplified model: it applies a standard navigation, performance or seamanship formula to the numbers you entered. True airspeed and density altitude use the ISA troposphere model for dry air and ignore humidity, compressibility and instrument or position error, so they are not a substitute for your aircraft's flight manual or an air data computer. Wind, climb, descent and fuel figures assume a steady wind and a constant speed and fuel flow for the whole leg; they ignore manoeuvring, holding, taxi and start-up fuel, terrain, turbulence and air traffic control routing. Takeoff distance scales an entered sea level figure by a rule-of-thumb percentage per 1000 ft of density altitude and is not a certified performance chart. Weight and balance results depend entirely on the arms and weights you enter and must be checked against the approved loading envelope. Hull speed is the classic 1.34 × √LWL displacement estimate, boat fuel burn is a horsepower-based approximation, anchor scope is a rule of thumb, and the rule of twelfths is a linear approximation of a sinusoidal tide that does not hold in all locations. Always use official charts, tide tables, the aircraft or vessel manuals and current weather, and treat these numbers as planning estimates only.
More in Aviation and marine
See all →Frequently asked questions
What does the center of gravity position tell you?+
It's the single point along the aircraft's length where its total weight can be considered to act, expressed as a distance from the datum or as a percentage of mean aerodynamic chord (MAC). It must fall within the manufacturer's approved forward and aft limits for safe flight.
How is center of gravity position calculated?+
It's the total moment (sum of all individual weight × arm calculations) divided by the total weight: CG = total moment ÷ total weight. This gives the effective arm at which the whole aircraft's weight balances.
Why is a CG too far aft dangerous?+
An aft CG reduces the aircraft's natural pitch stability and can make it harder or impossible to recover from a stall, since there's less tail-down force available to bring the nose down. It can also reduce elevator authority needed to control pitch at low speed.
Why is a CG too far forward also a problem?+
A forward CG increases stability but requires more elevator deflection to rotate on takeoff and to flare on landing, and in an extreme case the elevator may not have enough authority to raise the nose at all, especially at low speed with reduced elevator effectiveness.
What's a common misconception about CG limits?+
Pilots sometimes assume that if the aircraft is under maximum gross weight, the CG is automatically fine. In reality, weight and balance are independent checks — a load can be well under max weight and still fall outside CG limits depending on how it's distributed.